A video content provider or distributor may deliver various video contents to subscribers or users using different coding schemes suited for different devices, such as televisions, notebook computers, and mobile handsets. The video content distributor may support a plurality of video encoder and/or decoders (codecs), video media players, video frame rates, spatial resolutions, content bit-rates, end-devices, or combinations thereof. A video content may be converted from a source or original representation to various other representations to suit the different user devices and different distribution networks.
With increasing numbers of network types, user device types, and content representations, a video content distributor may need to store different versions or representations of the same video content on a source server or a rented content delivery network (CDN) node to satisfy the needs of various user devices. The storage of multiple representations may increase a cost of content distribution (e.g., increased storage space in the source server or increased fee to rent the CDN node). To avoid storing multiple representations, a video transcoder may be introduced onto the source server or CDN nodes and configured to convert a video content from one representation to another, as requested by user devices. Thus, video transcoding may enable a seamless interaction between video content creation and consumption.
In content preparation and delivery, transcoding devices (i.e. transcoders) implemented in CDN nodes, gateways, multipoint control units or servers, may be third party hardware and/or software. For example, content distributor NETFLIX may rent a third party transcoder belonging to AMAZON or AKAMAI, in which case the transcoder may be un-trusted by NETFLIX or its subscribing users. In existing video content delivery schemes, a video content going through a transcoding process may be completely exposed to the un-trusted third party transcoder. Consequently, privacy of users subscribing the video content, and the confidentiality and copyright of the video content may not be sufficiently protected.